I was newly faced to an astonishing combo I couldn't beat, let's call it the "Procession-Armory-Duchy-Rush":
The kingdom was something like
2 Cellar
3 Ambassador
3 Oracle
4 Procession
4 Armory
4 Scavenger
5 Horn of Plenty
5 Festival
.. and two more cards I have forgotten. Let it be thief and scout, if you want so
My opponent went first and opened armory/silver, bought two processions on move 3/4 and played his armory on move 4, topdecking another armory.
I opened double ambassador, in move 3/4 i ambassadored two coppers and one estate, and i bought a silver on move 4.
On move 5, he played procession-armory, topdecked a procession and an armory, trashed his first armory into a duchy and bought an estate(!).
Seeing this, I figured out, that his plan was to repeat procession-armory->duchy, three-pile-ending the game before I got enough provinces ... and this is exactly what happened.
Now, I have three questions:
1) Was my double ambassador already a mistake?
2) What would you do in my position, confronted to procession-armory-duchy?
3) Is this combo really strong? At least, it is almost sure you can set it up within 5 to 7 moves, and it can hardly be stopped (minions, pillages and pin strategies put aside).